Process of treating ores



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T. P. BARBOUR. V PROCESS 0F TREATING GRES.

110.571,468. Patented Nov. 17, 1896.

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T. P. BARBOUR.

PROCESS 0F TRBATING ORBS. 4 No. 571,468. Patented Nov. 17, 1896. F77

l Armar Fries,

THOMAS P. BARBOUR, OF SAN ANTONIO, TEXAS.

PROCESS OF TREATING ORES.

SPECIFICATION forming part of Letters Patent No. 571,468, dated November17, 1896. Application filed November '7, 1893. Serial No. 490,294. (Nomodel.)

T0 @ZZ whom it may concern.-

Be it known that I, THOMAS P. BARBOUR, a citizen of the United States,residing at San Antonio, in the county of Bexar and State of Texas, haveinvented a new and useful Process of Treating Ores, of which thefollowing is a speciiication.

This invention relates to processes of treating ores; and it has for itsobject to provide an improved method of reducing gold and silver oresand recovering their metals.

To this end the main and primary object of the present invention is toprovide an improved process of the character described which isavailable for use in connection with all classes of gold and silverores, but which is more especially adapted to refractory ores in theirraw state, and is therefore particularly designed to provide a simpleand efficient process for the treatment or ores in their raw statewithout the necessity of roasting The more or less complicated nature ofthe refractory ores of gold and silver, and the extremely intractablecharacter of some of their constituents, make the treatment thereof bymost ordinary methods very difficult and in many cases utterlyimpracticable, and thereby leaving the roasting process, with or withoutsalt, as the only really practical method now in use preparatory to thechlorination of Jthe ores. Vhile this roasting process is eiiicient inproducing the results required of it, it is nevertheless attended withmany disadvantages from standpoints of complication and expense, and thepresent invention is therefore particularly useful in the dispensingwith this step.

iVith these and other objects in view the invention consists in thenovel process hereinafter fully described and claimed, taken inconnection with certain apparatus necessary to the successful carryingout of the process, and which apparatus is illustrated in theaccompanying drawings, in which-.-

Figure lis a side elevation of the chlorinating-tank. Fig. 2 is acentral longitudinal sectional vieW of the same. Fig. 3 is a sectionalview of the metal-precipitating tank. Fig. 4 is a detail sectional Viewof an ordinary leaching-tank sometimes used in connection with theprocess.

The construction of the apparatus illustrated in the accompanyingdrawings will be referred to particularly in connection with the processcarried out by the same as the description of such process is proceededwith, and taking the first step of the process it is to be understoodthat the ore to be treated in its raw state is first pulverized by anyof the improved methods of crushing or stamping ores, but preferably bystamps, to an eightymesh ineness, that is to say, to such a linenessthat it will pass through battery-screens of eighty meshes to the inch.Fine pulverization is essential in order to secure the best results, asit has been found by practical experience and observation that for thepurposes of reduction and extraction the finer the ore is pulverized thebetter the process can be carried out.

A charge of the pulverized ore is fed into theV chlorination tank orcask A, through the manhole a, in such quantity that when fully chargedwith ore, Water, and chemicals only two-thirds of the capacity of thetank or cask shall be taken np, it having been proven by practicalexperiment that the very best results are secured by mixing at or belowthis point.

The chlorination-tank A is essentially a large stout cask made,preferably, of Wellseasoned oak, thoroughly soaked with paraffin, andstrongly bound with iron bands and castings proportioned throughout tothe load which' the tank is designed to carry. The said tank issupported in a horizontal position and is provided at a point betweenboth ends thereof and its center With the flanged guide-rings B,completely encircling the same and turning on the vertical guide-rollsO, secured to the horizontal drive-shaft D. The horizontal drive-shaft Dalso carries the drivepinions E, Which mesh with the spur-rings F,secured exteriorly on the tank, near the opposite ends thereof, and saidshaft D may be driven from any suitable driving machinery and providesmeans `whereby the tank is given a smooth and regular rolling motion,said rings B -preventing all slipping or lateral motion. The manhole ais placed longitudinally of the tank, at a central point thereof, andprovides means whereby the said tank may be charged with the ores,chemicals, dac., and

in order to provide means for the discharge IOO of the contents of thetank the same is provided with a circular series of metal-linedbung-holes G, regularly spaced apart and kept closed during the rotationof the tank by means of well-fitting wooden bungs H, which aresufficiently long to project beyond the outer surface of t-he tank tofacilitate their removal when necessary.

Arranged inside of the tank A., at a point adjacent to and parallel withthe opposite end heads thereof, are the metallic pole-disks I. Thesepole-disks are solid plates of copper designed to be deeply chined intothe body of the tank, so as to make water-tight joints, and are intendedto serve as poles for the transmission of electric currents through theiiuid pulp, which fills the whole space intervening between them. Toprevent the sagging and bending of the pole-disks under the outwardpressure of the ore under treatment, and at the same` time completelyinsulating them, insulator bracing-posts J are arranged between thedisks and the outer heads of the tank. Connecting-pins K project throughand' are insulated from the opposite heads of the tank and are connectedat their inner ends to the pole-disks, while to their outer extremitiesare connected the circuit-wires 1 2, which are connected in circuit witha suitable battery or other electric generator. rlhe tank thus describedbeing charged with the proper quantity of ore, finely-pulverized blackoxid of copper (monoxid) is added in the proper proportion of about sixor eight pounds to a ton of ore and the mixed ores treated withsufficient water to make a pulp of the consistency of thin mortar. Themanhole a is now closed and sealed and one of the upper bungs removed,and into this open bung-hole sulfuric acid 7is carefully introduced in aquantity equaling about twothirds of the weight of the copper oxidemployed; but, if found desirable, instead of introducing the chemicalsin this manner the oxid of copper may be treated with water and sulfuricacid in a separate vessel andthe resulting pulp, when the combination isfinished, added to the charge of ore.

After the oxid of copper and the acid have been introduced into thetank, together with the pulverized ore, the rotation of the tank isbegun. This rotation should continue for at least one hour and a half,or as long as may be found necessary, and after a sufficient agitationof the materials contained within the tank it will be found that suchmaterials have become thoroughly mixed and the various reactionscompleted by which the gold and silver are reduced to such a conditionas to be readily seized by chlorin gas. These reactions and theirrationale are not sufficiently clear for a character explanation of thesame, but for the purposes of the present invention it is thought to besufficient to state that this preliminary treatment of the ores is aperfect substitute in every respect for the ordinary roasting process,and pren pares the ores whereby a very rapid chlorination thereof may beeffected. After the preliminary treatment of the ore in the manner justdescribed the rotation of the tank is stopped and a second chargeintroduced into the same, consisting of eight pounds of black oxid ofmanganese, thirty pounds of salt, and twelve pounds of sulfuric acid, orin lieu thereof any suitable bisulfate in equivalent proportions. rl`hetank is again given a roll.- ing motion through the means described andthe electric current closed over the circuit 1 2, so that thechlorinating-tank, by reason of the pole-disks therein, will be includedin such circuit, whereby electric currents may be continually passedthrough the pulp within the tank during the rotation thereof, and thesecurrents are maintained until the chlorination is completed. Ordinarilyan hour and a half or two hours suffices to complete the chlorination,according to the strength of the electric current, and this rapidchlorination is primarily due to the favorable condition in which t-heores of the precious metals are left by the oxid-of-copper treatment,combined with the powerful energizing effect of the electric currents onthe reagents employed, as well as to the intimate mixture brought aboutby the constant agitation, whereby every particle is brought intointimate contact with the nascent chlorin at the very instant of itsgeneration. After the chlorination is completed the circuit over thewires l 2 is broken, while the tank still continues to revolve. One byone as the bungs come into a favorable position the same are loosened bya smart blow of ahammer and are at once driven out by the force of thepulp, which, being kept fluid by constant agitation, at once finds ventor escape through the open bung-holes, and continues to do so till thetank is completely emptied, such pulp, as it is delivered, being adaptedto fall into a suitable gutter or trough L, (shown in dotted lines,) bymeans of which it maybe conveyed to the desired point. After the pulphas been discharged from the chlorinating-tank, as just noted, all thebungs are secured in the holes, excepting one of the lower ones, and ahose is introduced through the manhole, whereby the interior of the tankmaybe thoroughly cleaned of any pulp remaining, the wash-water runningout of the lower bung-hole and being conveyed to mix with thechlorinated pulp. At this stage of the process the gold and silver ofthe ore are held in solution in the form of the chlorids of such metals,and if the details of the chlorination have been properly managed not agrain of either the gold or silver will be found in the pulp or solidmatter. This enables the remainder of the process or treatment of theores to be carried out either by amalgamation or lixiviation, by eitherof which methods the gold and silver can be recovered with nearly equalresults. In case the next step of the process is the preparation of thematerials for amalgamation, the chlo- IOO lIO

rinated ore and wash-water is conveyed directly to themetal-precipitating tank M, the agitator of which is already in motionwhen the chlorinated pulp is introduced, so as to keep the pulp fluidand in good working condition, whereby no time maybe lost between thechlorination and precipitation, so that the conversion of the chlorid tometallic silver is going on in the tank M during the discharge of thepulp from the chlorinating-tank, and to secure this result advantage istaken of the electrolytic action of zinc upon the salts of silver andthat action stimulated and intensified by an electric current.

The metal-precipitating tank M is an open circular vessel of suitablesize arranged vertically and preferably made with oak sides and an ironbottom, to which is secured a closed steam-chamber N, in which is keptup a circulation of steam in order to heat up the tank to facilitate andexpedite the precipitation of the silver from its chlorid solution.Suitably mounted inside of the metal-precipitating tank M is a verticalagitator-shaft O, driven by suitable shaft connections and carryinginside of said tank a radial series of horizontal agitator-arms l),disposed at right angles to the shaft and carrying` a `vertical seriesof square or diamond shaped agitatorbars Q, of solid zinc, and whichbars extend above the upper arm to the usual level of the pulp and belowthe lower arm to within onequarter of an inch of the bottom. These zincagitator-bars are adapted not only to agitate the fluid pulp within themetal-precipitating tank, but also act in an auxiliary capacity togetherwith the circuit-plates R. The zinc circuit-plates R are secured to theinterior Wooden surface of the tank by suitable screws, and are of aheight equal to the average depth of the pulp in the tank, but terminateshort of the metallic bottom of the tank. Two adjacent zinc plates,atone side of the tank,are provided with the upper extensions S, reachingto the top of the tank and carrying bindingscrews T, to which areconnected the terminals of the circuit-wires 3 4, which are adapted tobe included in a suitable generator-circuit and so arranged that thedirection of the electric current entering the tank shall be the same asthe direction of the rotation of the agitator therein.

As soon as the electric circuit is broken on the wires l 2 and thecurrent is thereby cut oft` from the chlorinating-tank the circuit isclosed over the wires 3 and 4 through the tank M, so that the operationof precipitation and agitation in the tank M may be commenced while thetank A is discharging. It will be well understood by those skilled inthe art that the iiuid pulp while it is agitated in the tank M comesunder the iniiuence of the zinc intensified by the currents ofelectricity playing in every direction throughout the said tank, therebyproviding means for very quickly precipitating metallic silver from itschlorid solution, and it has been the precipitation of the metallicsilver from the pulp solution in the tank M the electric current is cutoft and the pulp allowed to settle to the bottom of the tank. Thesolution is now drawn off into any suitable receptacle or tank,providing convenient means whereby the gold may be precipitated from thesolution by ordinary methods, as will be hereinafter referred to, andafter this solution is drawn o the tank M is filled with water to apoint corresponding to the height of the first solution. Agitation isagain commenced and continued a suitable length of time, after which thepulp is allowed to settle and the clear solution drawn off into thevessel or tank containing the gold solution. More water is now added tothe. pulp to give to the same a suitable consistency, and from two tofive pounds of salt and about two pounds of fine granulated zinc added.The pulp, together with the added salt and zinc, is now taken from thetank M and passed to an amalgamatin gpan for treatment. This pan may beof any improved modern type, but is preferably one of that characterheated by steam. Quicksilver is added in the usual way and in a quantityto suit the requirements of the process. Agitation is begun in theamalgamating-pan as soon as the pulp is transferred and is kept up untilamalgamation is complete. The pulp is then thinned and transferred tothe settler, where, being properly washed, the amalgam is collected andretorted and the silver product run into bars. This amalgamation step iswell understood by those skilled in the art and need not be furtherdescribed.

After the chlorination of the ores, if itis desired to proceed by themethod of lixiviation, the chlorinated pulp and solution from the tankA, instead of in the first instance being conveyed to the tank M, as inthe amalgamation process, is conveyed directly to the leachingtank U,having a false perforated bottom V and an ordinary revolvingrakeagitator XV, which is of the ordinary construction employed inprocesses of this character. Vater is added to the pulp as it isintroduced into the leaching-tank and agitation set up so as tothoroughly mix the water with the pulp. Now the solution which, it mustbe remembered, carries all the gold and silver chlorids is leached offand conveyed to the tank M, in which agitation has already been startedand the proper electric connections made. Fresh water is added to thepulp in the leaching-tank, thoroughly agitated in the pulp, and thenleached off to be .mixed with the iirst solution in the tank M. Nowsimply the chlorids of gold and .silver in solution, without the pulp,are in the metal-precipitating tank M, and the method of procedure issubstantially the same as that IOO IIO

previously described in connection with such tank. Agitation is kept upuntil the chlorid of silver in solution is decomposed by the combinedelectrolytic action of Zinc, salt, and the electric current, so thatpure metallic silver in a fine powder deposits itself on the bottom ofthe tank M. The action in the tank M is continued until all the silverin the solution has been precipitated, when the agitation is stopped andthe electric current broken, so that the solution may be left tothoroughly settle. As soon as this takes place the solun tion is drawnoff carefully, so as not to disturb the precipitate, and is conveyed toa suitable vessel or tank for the precipitation of the gold, as alreadyreferred to. The silver precipitate from the tank M is collected,washed, dried, and fused for bullion.

After the silver has been recovered by either amalgamation orlixiviation, as described, attentionis next directed to the goldsolution contained in any suitable tank or vessel. To this gold solutionis added a solution of protosulfate of iron, and if gold be present itwill be precipitated as a dark-brown powder, which is pure metallicgold. This solution is allowed to also settle fully and is then drawnoff into another suitable vessel or tank, while the gold powderremaining is collected, fused, and run into bars.

To the solution drawn off from the gold precipitate a solution ofcaustic potasli is added, whereby zinc, if present, may be recovered inthe form of a White amorphous powder, which, when heated, becomesZincoxid or the zinc-white7 of commerce; and if it is desired toascertain if copper be present in the ores the solution from the Zincprecipitate is treated with scrap iron, which causes the copper to bedeposited in a metallic state as a very fine dust, which may becollected and used in that state or fused, as preferred.

From the foregoing it is thought that my improved process for recoveringgold and silver from their ores will be fully understood by thoseskilled in the art, and I would state that I am aware that zinc has beenemployed as a precipitant of silver from both cyanid and hyposuliitesolutions, and in this connection it is to be noted that the processinvolved fil 571,468

by the present invention prepares the materials in such a manner wherebythe precipitation by zinc is effected from the original solution withoutemploying any chlorid solvent, such as cyanid of potash or hyposulfiteof soda.

It is to be understood that slight changes in my process may be resortedto without departing from the spirit of the present invention, for inthe employment of copper oXid and sulfuric acid in the preliminarytreatment of the ore I do not confine myself to that combination, butmay also use metallic copper with sulfate of copper, or even sulfate ofcopper alone, according to the nature of the ore, and such other minorchanges as might be found expedient to observe.

Having thus described the invention, what is claimed, and desired to besecured by Letters I)atent, is

l. The herein-described process of treating ores which consists in firsttreating the raw material with copper oXid and sulfuric acid, thenchlorinating the pulp thus treated, introducing the chlorinated massinto a suit able agitator having Zinc therein, and establishing anelectric current through the mass in the presence of zinc, substantiallyas set forth.

2. A chlorinating-tank for treating ores consisting of a revoluble caskhaving a single manhole and a circular series of bung-holes, copperpoledisks secured within the cash at opposite ends thereof and arrangedin an electric circuit, insulator bracing-posts arranged between saiddisks and the outer heads of the tank, flanged guide-rings encirclingsaid eask at an intermediate point, spurrings encircling the cask nearits opposite ends, and a horizontal drive-shaft carrying guide-rollsengaging said iianged guide-rings and drive-pinions engaging saidspur-rings, substantially as set forth.

In testimony that I claim the foregoing as my own I have hereto aiiixcdmy signature in the presence of two witnesses.

THOMAS P. BARBOUR. Vitnesses:

W. W. ToBEY, MILFORD P. NORTON.

